1. Field of the Invention
This invention relates to improvements in a lubricating oil supply system for an infinitely variable transmission in which an infinitely variable transmission has a transmission shaft rotatably mounted through a wall section attached on the casing, provided with a lubricating oil path, and housed in a transmission case formed in the casing partly defined by the wall section. An input rotary member is relatively unrotatably coupled with the transmission shaft outside of the transmission case. And an oil pump for supplying the lubricating oil to the lubricating oil path is located in the casing.
2. Description of Background Art
This type of lubricating oil supply system has already been known as disclosed in Japanese Patent Laid-Open Nos. Hei 11-79054 and Hei 11-270641 for example.
In the case of the lubricating oil supply system disclosed in Japanese Patent Laid-Open No. Hei 11-79054, the oil pump is driven by a crankshaft which is located apart from the transmission shaft of the infinitely variable transmission. The oil passage from the oil pump to the lubricated area of the infinitely variable transmission, therefore, increases in length. In addition, the oil supply passage becomes complicated in structure.
In the meantime, in the lubricating oil supply system disclosed in Japanese Patent Laid-Open No. Hei 11-270641, an oil pump is mounted on the same axis as the transmission so as to be driven by the transmission shaft, whereby the structure of the oil passage is simplified. However, in the lubricating oil supply system disclosed in Japanese Patent Laid-Open No. Hei 11-270641, the oil pump is located outside of an input gear fastened on the transmission shaft on the outside of the transmission case which is partly defined by the wall section of the casing. The oil passage from the oil pump to the lubricated area of the infinitely variable transmission is shorter than that in the lubricating system disclosed in Japanese Patent Laid-Open No. Hei 11-79054, but is not substantially decreased in length. In addition, the transmission shaft projects largely out of the wall section, resulting in upsizing of the whole body of power train inclusive of the infinitely variable transmission.
In view of the above-described disadvantages inherent to prior art lubricating oil supply systems, the present invention has as its object the provision of a lubricating oil supply system for an infinitely variable transmission which enables simplification of the structure of an oil passage provided between an oil pump and a lubricated area of the infinitely variable transmission.
To accomplish the above-identified object, the present invention includes an infinitely variable transmission that has a transmission shaft rotatably mounted through a wall section attached on the casing, and provided with a lubricating oil path, and housed in a transmission case formed in the casing partly defined by the wall section. An input rotary member is relatively unrotatably coupled with the transmission shaft outside of the transmission case. And an oil pump for supplying the lubricating oil to the lubricating oil path is located in the casing. In this lubricating oil supply system the oil pump driven by the transmission shaft is located on the wall section.
According to the lubricating oil supply system of the above-described constitution, the oil pump is driven by the transmission shaft mounted through the wall section located axially inside of the input rotary member, and therefore it is possible to simplify the structure of the oil passage formed from the oil pump to the lubricating oil path in the transmission shaft. Furthermore, as the oil pump is mounted adjacent to the infinitely variable transmission, the oil passage from the oil pump to the lubricated area of the infinitely variable transmission can be substantially simplified and besides the transmission shaft can be decreased in length by connecting the input rotary member to the end of the transmission shaft.
According to a second aspect of the present invention, the infinitely variable transmission has the transmission shaft, a driving rotary member relatively unrotatably coupled with the transmission shaft, a driven rotary member relatively rotatably supported on the transmission shaft, a carrier movable along the axis of the transmission shaft, a support shaft having its axis along the conic generating line on the center of the axis of the transmission shaft and supported on the carrier, and a shifting rotary member having a conical first friction transfer surface in contact with the driving rotary member and a conical second friction transfer surface in friction contact with the driven rotary member and rotatably supported on the support shaft; the transmission shaft being provided, at an area corresponding to the infinitely variable transmission, with a plurality of oil feed holes communicating with the lubricating oil path at the inner end and open in the outside surface of the transmission shaft at the outer end. It is, therefore, possible to effectively apply the present invention to the infinitely variable transmission which steplessly changes the gear ratio by moving the carrier in the direction of axis of the transmission shaft.
According to a third aspect of the present invention, the oil pump has rotors connected to the transmission shaft in a pump housing formed of the wall section and a cover connected to the wall section; a filter protruding into an oil sump in the casing is mounted on the lower part of the wall section; and an inlet oil path for connection between the filter and the oil pump and a discharge oil path for leading the lubricating oil discharged from the oil pump are provided in the wall section. According to this constitution, it is possible to form an oil passage of compact and simple construction extending from the oil sump to the oil pump. The power transmitting device including the infinitely variable transmission, therefore, will not be upsized by the formation of the oil passage.
Furthermore, according to a fourth aspect of the present invention, there is formed a ring-shaped oil path between the wall section and the transmission shaft, surrounding the transmission shaft and communicating with the discharge oil path; the transmission shaft is provided with a connecting hole between the lubricating oil path in the transmission shaft and the ring-shaped oil path. According to this constitution, it is possible to perform lubrication between the wall section and the transmission shaft while shortening and simplifying the oil passage between the oil pump and the lubricating oil path.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.